RESERVE FOR LOSSES AND LOSS EXPENSES (DETAILS 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of Beginning and Ending Gross Unpaid Losses and Loss Expenses
Gross reserve for losses and loss expenses, beginning of period	$ 9,058,731	$ 8,425,045	$ 7,032,375
Less reinsurance recoverable on unpaid losses, beginning of period	(1,825,617)	(1,736,823)	(1,540,633)
Net reserve for unpaid losses and loss expenses, beginning of period	7,233,114	6,688,222	5,491,742
Net incurred losses and loss expenses related to:
Current year	2,353,631	2,340,868	2,932,513
Prior years	(219,436)	(244,840)	(257,461)
Net incurred losses and loss expenses	2,134,195	2,096,028	2,675,052
Net paid losses and loss expenses related to:
Current year	(318,006)	(322,836)	(509,075)
Prior years	(1,373,459)	(1,299,384)	(953,035)
Net paid losses and loss expenses	(1,691,465)	(1,622,220)	(1,462,110)
Foreign exchange and other	6,184	71,084	(16,462)
Net reserve for unpaid losses and loss expenses, end of period	7,682,028	7,233,114	6,688,222
Reinsurance recoverable on unpaid losses, end of period	1,900,112	1,825,617	1,736,823
Gross reserve for losses and loss expenses, end of period	$ 9,582,140	$ 9,058,731	$ 8,425,045